1. Field of the Invention
This invention relates to a laser recording apparatus for effecting recording on a recording medium by use of an array of semiconductor lasers.
2. Description of the Prior Art
There has been proposed and broadly utilized a laser recording apparatus of such a type that an endless recording medium such as a photoreceptor or the like is movably supported and scanned by a beam of laser light in a primary direction substantially perpendicular to the moving direction of the recording medium to effect an image-formation.
The scanning of the laser in the primary direction is accomplished by use of a vibrating mirror or a rotating multifaceted mirror as scanning means. In order to increase the recording operation in velocity, such scanning means must be driven at higher velocity. In any event, however, the increase of scanning in velocity is limited. Even if the multifaceted mirror which can be rotated at high speed is utilized, it is difficult to maintain the rotation thereof at a velocity in the order of 20,000 r.p.m. in a stable manner because there are various problems with respect to bearing technique and the like.
In order to overcome these problems, an AO modulator for large-sized laser such as He-Ne laser or the like has been broadly used to divide the beam of the laser. In such a proposal, however, a laser recording apparatus cannot be decreased in size because the laser source and AO modulator are large.
On the other hand, there has been developed a semiconductor element which can be used as a source of laser beam. If such a semiconductor element is used as a single source of laser beam, AO modulator which is inconvenient for decreasing the laser recording apparatus in size must be utilized. There has been also developed an array of semiconductor lasers for providing multiple sources of laser beam. In such a proposal, it is difficult to position these sources of laser beam with a distance from one to another which is less than about 100.mu. because there are problems with respect to heat generation in sources of laser beam, manufacturing accuracy and the like. In an optical system for scanning which utilizes such sources of laser beam, light spots are extremely spaced from each other on the recoring medium so that it will be almost unable to record.